1. Field of Invention:
This invention relates to a compact, self-aligning optical transceiver, and more specifically to a transceiver with optical components suspended in a frictionless manner either electromagnetically or pneumatically and protected from a wide range of relative carrier movement and acceleration.
2. Discussion of Prior Art:
Prevalent data transmission or communication links use radio and microwave transmission. There is a need for a new device to alleviate the problems of congestion, intermittent interference and possible interception and of shared radio and microwave frequency bands. Optical data links using line-of-sight transmission have been suggested. Following are patents and literature references illustrating devices using lasers for communication.
U.S. Pat. No. 4,867,560 relates to a satellite communication system having a dual-beam optical alignment system for automatic adjustment of the axes of beams of different wave lengths into a predetermined optical axis.
U.S. Pat. No. 4,933,928 shows an optical communications terminal apparatus for sending and receiving transmissions to and from a plurality of remote stations by a plurality of independent terminals using a multiplexer. All of the transmitted and received modulated beams have different wavelengths; they are separated by wavelength and directed to their correct destinations.
U.S. Pat. No. 4,882,772 relates to communications signal transmission systems particularly to electro-optical light beam television, telephone and digital data transmission systems specifically for urban installations to replace cables, and needs manual alignment with the aid of a telescopic sight. The system also includes a heat sink for dissipating heat from a laser generator.
Published references include "Shipboard Electro-Optical System Integration," by Robert J. Giannaris, et al,. pp 120 -125, SPIE Vol. 103, Systems Integration & Optical Design II (1977); and "Pointing, Acquisition and Tracking for Intersatellite Optical Data Links," by W. Auer, pp. 131 -136, Proc. ESA Workshop on Space Laser Applications and Technology, Les Diablerets, March 1984. Both these references disclose apparatus having pointing, acquisition and tracking capabilities and use a laser.
None of the above references relate to a system for suspending components of an optical transceiver in a frictionless manner by means of electromagnetic motors. This is achieved in the present invention by two thin profile orthogonally nested electromagnetic motors, herein referred to as pancake motors. Alternatively the motors may have pneumatically assisted suspension. When activated, the motors will work in concert with each other and with controlling logic to suspend the transceiver's optical components and enable accurate pointing of its transmission beam.
The preferred embodiment of the transceiver of this invention, hereafter referred to as the "transceiver", is described in detail in following sections of the drawing. Refer to FIG. 2 for an overall illustration of the transceiver. The transceiver has been designed to accomodate a wide variety of applications with little or no variation of components as described for the following intended applications.
The transceiver provides a universal mounting system which adds a third motor axis to the two pancake motor axes supporting the optical platform so as to enable alignment of the beam in any direction relative to the carrier mounting. This full surround movement will facilitate mobile mountings and applications requiring a panoramic alignment capability.
Applications can be classified as either independent or dependent mode. When operating in independent mode, a transceiver is not dependent upon receiving a beam emitted from one or more cooperating devices thus forming a cross-link.